International Journal of Contemporary Pediatrics Reddy KV et al. Int J Contemp Pediatr. 2020 Jun;7(6):1441-1443 http://www.ijpediatrics.com pISSN 2349-3283 | eISSN 2349-3291 DOI: http://dx.doi.org/10.18203 /2349-3291.ijcp20202164 Case Report Two cases with pycnodysostosis in a family: a case report K. Venkataramana Reddy1*, Chapay Soren1, M. Geethika2, V. Malathi1 1Department of Pediatrics, 2Department of Radiodiagnosis, SVS Medical College, Mahabubnagar, Telangana, India Received: 06 February 2020 Revised: 28 April 2020 Accepted: 05 May 2020 *Correspondence: Dr. K. Venkataramana Reddy, E-mail: [email protected] Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Pycnodysostosis (Greek, pycnos - density, dys - defect, ostosis - bone) is a rare inherited disorder of the bone, first described by Maroteaux and Lamy. Pycnodysostosis is an autosomal recessive disorder, with incidence estimated to be 1.7 per 1 million births. Clinical presentation of this disorder include short stature, dolichocephalic skull, frontal bossing, obtuse mandibular angle, dysplastic clavicles, and short hands and feet, diffuse osteosclerosis, acro- osteolysis along with the finger and nail abnormalities. The main oral aspects are midfacial hypoplasia, a grooved palate, and dental abnormalities include double row of teeth, delayed eruption of permanent dentition, multiple caries. Pathological fractures of the bones occur due to sclerosis. Radiologically, skull bones appear thickened with open fontanels which look like ‘lakes of bones’, hypoplasia of facial bones, generalized osteosclerosis, open fontanels and cranial sutures, non pneumotization of paranasal sinuses, and fractures commonly in lower limbs. Keywords: Hypoplasia, Osteosclerosis, Paranasal sinuses, Pycnodysostosis, Short stature INTRODUCTION multiple caries. Pathological fractures of the bones occur due to sclerosis.4,5 Pycnodysostosis (Greek, pycnos - density, dys - defect, ostosis - bone) is a rare inherited disorder of the bone, Radiologically, skull bones appear thickened with open first described by Maroteaux and Lamy.1 fontanels which look like ‘lakes of bones’, hypoplasia of facial bones, generalized osteosclerosis, open fontanels Pycnodysostosis is an autosomal recessive disorder, with and cranial sutures, non pneumotization of paranasal 6 incidence estimated to be 1.7 per 1 million births; occurs sinuses, and fractures commonly in lower limbs. due to lysosomal storage disease of the bone caused by a mutation in the gene that codes the enzyme cathepsin K.2 CASE REPORT Phenotypic features of this disorder include short stature, Here, we report two siblings (Figure 1) with typical dolichocephalic skull, frontal bossing, obtuse mandibular features of pycnodysostosis, both clinical and angle, dysplastic clavicles, and short hands and feet, radiographical. diffuse osteosclerosis, acro-osteolysis along with the finger and nail abnormalities.3 Case 1 The main oral aspects are midfacial hypoplasia, a Child 1- A 9 year old male came with complaints of not grooved palate, and dental abnormalities include double gaining adequate height. He was born to a second degree row of teeth, delayed eruption of permanent dentition, consanguineous marriage. Examination revealed height International Journal of Contemporary Pediatrics | June 2020 | Vol 7 | Issue 6 Page 1441 Reddy KV et al. Int J Contemp Pediatr. 2020 Jun;7(6):1441-1443 107cm (<3rd percentile for his age) with US: LS ratio of The radiological survey of limbs and skull findings 1:1.1, weight 16kg (<3rd centile), and head circumference (Figure 2 and 4) widely separated cranial sutures with 50.5cm (<3rd percentile). He has coarse facial features widely open anterior and posterior fontanel; non- with frontal bossing with open fontanels measuring pneumatised paranasal sinuses and obtuse angle of the 6x5.5cm; restricted opening of mouth, beaked nose, mandible. Skeletal x rays of longs bones showing diffuse crowded teeth, with chest deformity. The hands and feet skeletal hyperostosis with sparing of medullary cavity had short terminal phalanges, broad based and dysplastic (Figure 3). The bone age was equal to his chronological nails with koilonychia. age for both the siblings. Both the brothers had moderate bilateral conductive hearing loss. Eye examination findings were normal. Both the siblings had similar characteristic clinical and radiological findings suggestive of Pycnodysostosis. A B Figure 1: Two siblings 7 and 9 years, with frontal bossing, and short stature. Case 2 Child 2- Younger sibling of child 1, 7 year boy, was also brought for not gaining adequate height. His height was Figure 3: Case 1 (A) X- Ray wrist and hand showing 102 cm (<3rd percentile) with US: LS ratio of 0.86cm, thickened cortex with narrow medullary space and weight 14kgs (<3rd percentile), head circumference 47cm osteosclerosis of the phalanges. (B) X- Ray of lower (<3rd percentile) with open anterior fontanels measuring limbs showing healed and calcifies fractures with 5.5x5.5cms. He also had coarse facial features, cortical thickening overcrowding of teeth and chest deformity, short and broad phalanges with dysplastic nails. Figure 4: Child 2 lateral view of X-Ray skull, showing Figure 2: Case 1 X- Ray skull lateral view showing wide opened anterior fontanel, hypoplasia of mid face, wide opened anterior fontanel, non pneumotized obtuse mandibular angle and with non pneumotized sinuses, and obtuse angle of the mandible. paranasal sinuses. International Journal of Contemporary Pediatrics | June 2020 | Vol 7 | Issue 6 Page 1442 Reddy KV et al. Int J Contemp Pediatr. 2020 Jun;7(6):1441-1443 DISCUSSION 3. Rajan AR, Singh V, Bhave AA, Joshi CS. Pycnodysostosis: A rare cause of short stature. Med Pycnodysostosis is an autosomal recessive disorder of the J Armed Forces India. 2015 Oct;71(4):393-5. bone caused by an inactivating mutation in cathepsin K 4. Aynaou H, Skiker I, Latrech H. Short stature (CTSK), resulting from osteoclast dysfunction. The first Revealing a Pycnodysostosis: A Case Report. J case of pycnodysostosis was described in 1923 by Orthop Case Rep. 2016 Apr-Jun;6(2):43-5. Montanari; however, in 1962, typical features of 5. Khoja A, Fida M, Shaikh A. Pycnodysostosis with pycnodysostosis was described by Maroteaux and Lamy special emphasis on dentofacial characteristics. Case (Greek: pycnos = dense; dys = defective; osteon = bone). Rep Dentist. 2015;2015. The most common phenotype of pycnodysostosis is short 6. Nirupama C, Sarasakavitha D, Palanivelu S, Guhan stature, which was reported in 95.9% of the 97 reported B. Pyknodyostosis: A case report or rare entity. J cases. The next most common phenotype is an increase in Indian Acad Oral Med Radiol. 2013;25:161-3. bone density, which was reported in 88.7% of the 97 7. Xue Y, Cai T, Shi S, Wang W, Zhang Y, Mao T et patients, with an estimated prevalence of 1 to 1.7 per al. Clinical and animal research findings in million.7,8 pycnodysostosis and gene mutations of cathepsin K from 1996 to 2011. Orphanet J Rare Dis. 2011 The normal osteoclasts bone cells function is to reabsorb May;10;6:20. into the bone and build new bone.2 Impaired function of 8. Turan S. Current research on pycnodysostosis. this critical enzyme (CTSK) for bone remodeling and Intractable Rare Dis Res. 2014 Aug; 3(3):91-3. resorption by osteoclasts leads to the fragile and 9. Aghili H, Tabatabaei SM, Goldani Moghadam M. sclerosing nature of the bone in affected patients.9 It is Clinical and radiographic features of characterized by diffuse condensation of the skeleton Pycnodysostosis with emphasis on Dentofacial with thickening of the cortex and narrowing of the problems. Case reports in dentistry. medullary cavity.10 2017;2017:4352485. 10. Markatos K, Mavrogenis AF, Karamanou M, Cranial and maxillofacial features include frontoparietal Androutsos G. Pycnodysostosis: the disease of bossing, thick calvaria, open fontanelles and sutures, Henri de Toulouse-Lautrec. Eur J Orthop Surg hypoplastic paranasal sinuses, Wormian bones in the Traumatol. 2018 Dec;28(8):1569-72. lambdoidal region, relative proptosis, beaked nose, and 11. Fleming KW, Barest G, Sakai O. Dental and facial an obtuse mandibular gonial angle, often with relative bone abnormalities in pyknodysostosis: CT prognathism.11 Dental abnormalities such as hypoplasia findings. AJNR Am J Neuroradiol. 2007 of the enamel, obliterated pulp chambers, and Jan;28(1):132-4. hypercementosis are some of the most striking features of 12. Kamak H, Kamak G, Yavuz I. Clinical, this anomaly.12 The most evident clinical and radiographic, diagnostic and cephalometric features radiographic feature of PYCD, however, is the presence of pycnodysostosis in comparison with Turkish of frontal, parietal and occipital bossing. Beaked nose, cephalometric norms: A case report. Eur J Dent. groove in midpalate, midfacial hypoplasia, mandibular 2012 Oct;6(4):454-9. hypoplasia and overcrowded teeth and obtuse mandibular 13. Rodrigues C, Gomes FA, Arruda JA, Silva L, gonial angle are common findings.13 The differential Álvares P, da Fonte P, et al. Clinical and diagnosis is established with osteopetrosis, cleidocranial radiographic features of pycnodysostosis: A case dysplasia and idiopathic acro-osteolysis, osteogenesis report. J Clin